This invention relates to a group-supervisory apparatus for an elevator which is suited to alter the group supervision of the existing elevator already constructed.
A prior-art elevator control apparatus for altering the group supervision of an existing elevator is as shown in FIG. 5.
Referring to FIG. 5, numeral 1 designates the control unit of an existing elevator, and numeral 2 designates a control unit added for altering the group supervision of the existing elevator. The additional control unit 2 comprises a computer 2a which executes group-supervisory processing, a relay driver 2b which is controlled by the computer 2a, and a control relay-substitute relay 2c and a transfer relay 2d which are connected to the relay driver 2b. Besides, symbol 2e denotes an operating power source for the substitute relay 2c as well as the transfer relay 2d, symbol 2c.sub.1 denotes the normally-open contact of the substitute relay 2c, symbol 2d.sub.1 denotes the normally-open contact of the transfer relay 2d, and symbol 2d.sub.2 the normally-closed contact of the transfer relay 2d.
The control unit 1 of the existing elevator has a control relay 1a which is the direction relay or stoppage relay of an existing elevator control circuit, and a condition circuit 1b therefor. The control relay 1a and the condition circuit 1b are connected in series across an operating power source 1c. When the elevator group supervision is to be altered, a line 1d which connects the control relay 1a with the condition circuit 1b is disconnected as indicated by a mark x, and the control relay 1a and the condition circuit 1b are connected by another line 1e instead of the line 1d. Also, the normally-closed contact 2d.sub.2 of the transfer relay 2d is connected in series with the line 1e. Further, a series circuit consisting of the normally-open contact 2d.sub.1 of the transfer relay 2d and the normally-open contact 2c.sub.1 of the control relay-substitute relay 2c is connected in parallel with the normally-closed contact 2d.sub.2.
Owing to such changes, when the transfer relay 2d is energized through the relay driver 2b by a command given from the computer 2a, the control relay 1a is disconnected from the existing condition circuit 1b by the normally-closed contact 2d.sub.2 now opened, and the normally-open contact 2d.sub.1 is closed. Therefore, the control relay 1a is energized or deenergized depending upon the state of the normally-open contact 2c.sub.1 of the control relay-substitute relay 2c which is controlled by the command of the computer 2a.
Accordingly, when the control relay 1a is the direction relay or the stoppage determining relay, the control of the energization/deenergization of such a relay in the existing elevator control circuit is permitted by the computer 2a, with the result that the group-supervisory control of the elevator by the computer 2a becomes possible.
When the conditions of the control relay-substitute relay 2c which is controlled by the computer 2a are made the same as those of the condition circuit 1b, the same elevator control as that performed before the alteration can be realized, and when the conditions are made different from those of the condition circuit 1b, a different elevator control can be realized.
With the prior-art elevator control apparatus for altering the elevator group supervision as stated above, the group supervision is performed by energizing/deenergizing the control relay 1a of the existing elevator control unit 1 by means of the computer 2a of the additional control unit 2, and hence, the control apparatus needs to be designed with the full knowledge of the existing elevator control unit 1. This has posed the problem of difficulty in the alteration of the group supervision of an old elevator for which design materials etc. are not kept in custody or an elevator made by a manufacturer different from that of the additional control unit, for which drawings etc. are not readily available.